From: Peter Ujfalusi <peter.ujfalusi@ti.com>
To: Vinod Koul <vkoul@kernel.org>
Cc: <dmaengine@vger.kernel.org>, Rob Herring <robh+dt@kernel.org>,
Bjorn Andersson <bjorn.andersson@linaro.org>,
<linux-arm-msm@vger.kernel.org>, <devicetree@vger.kernel.org>,
<linux-kernel@vger.kernel.org>
Subject: Re: [PATCH v4 2/3] dmaengine: add peripheral configuration
Date: Fri, 9 Oct 2020 14:29:44 +0300 [thread overview]
Message-ID: <13fdee71-5060-83fc-d69d-8ec73f82fac4@ti.com> (raw)
In-Reply-To: <20201009111515.GF2968@vkoul-mobl>
On 09/10/2020 14.15, Vinod Koul wrote:
>>> If for any any reason subsequent txn is for different direction, I would
>>> expect that parameters are set again before prep_ calls
>>
>> But in DEV_TO_DEV?
>
> Do we support that :D
>
>> If we have two peripherals, both needs config:
>> p1_config and p2_config
>>
>> What and how would one use the single peripheral_config?
>
> Since the config is implementation specific, I do not think it limits.
> You may create
>
> struct peter_config {
> struct p1_config;
> struct p2_config;
> };
The use case is:
MEM -DMA-> P1 -DMA-> P2
or
P2 -DMA-> P1 -DMA-> MEM
or
MEM -DMA-> P2
or
P2 -DMA-> MEM
or
MEM -DMA-> P1 -DMA-> MEM
How would the DMA guess what it should do? How would the independent P1
and P2 would know how to set up the config?
>>
>> If only one of them needs config, then sure, the driver can pin-point
>> which one the single config might apply to.
>>
>> Or you chain the same type of peripheral and you would need different
>> config for tx and rx?
>>
>> - Péter
>>
>> Texas Instruments Finland Oy, Porkkalankatu 22, 00180 Helsinki.
>> Y-tunnus/Business ID: 0615521-4. Kotipaikka/Domicile: Helsinki
>
- Péter
Texas Instruments Finland Oy, Porkkalankatu 22, 00180 Helsinki.
Y-tunnus/Business ID: 0615521-4. Kotipaikka/Domicile: Helsinki
next prev parent reply other threads:[~2020-10-09 11:29 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-10-08 12:31 [PATCH v4 0/3] dmaengine: Add support for QCOM GSI dma controller Vinod Koul
2020-10-08 12:31 ` [PATCH v4 1/3] dt-bindings: dmaengine: Document qcom,gpi dma binding Vinod Koul
2020-10-12 18:57 ` Rob Herring
2020-10-13 7:02 ` Vinod Koul
2020-10-08 12:31 ` [PATCH v4 2/3] dmaengine: add peripheral configuration Vinod Koul
2020-10-09 9:04 ` Peter Ujfalusi
2020-10-09 10:30 ` Vinod Koul
2020-10-09 10:45 ` Peter Ujfalusi
2020-10-09 11:15 ` Vinod Koul
2020-10-09 11:29 ` Peter Ujfalusi [this message]
2020-10-12 6:09 ` Vinod Koul
2020-10-12 12:05 ` Peter Ujfalusi
2020-10-08 12:31 ` [PATCH v4 3/3] dmaengine: qcom: Add GPI dma driver Vinod Koul
2020-10-09 9:00 ` Peter Ujfalusi
2020-10-09 10:31 ` Vinod Koul
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